The development of Fresnel contrast analysis, and the interpretation of mean inner potential profiles at interfaces

This paper provides a summary of recent published and unpublished research on the development of Fresnel contrast analysis, a transmission electron mi croscopy technique for measuring the mean inner potential profile across an interface or a narrow layer. An algorithm for finding a best-fitting poten tial profile is described, energy-filtered experimental data are analyzed a nd contributions to Fresnel contrast from surface grooves and space charge are assessed. Many of the conclusions drawn are equally relevant for the in terpretation of phases measured using off-axis electron holography. (C) 200 0 Elsevier Science B.V. All rights reserved.